The Primary Breast Cancer Therapy Group (NSABP) was originally established in 1958 and presently has 80 nurse/data managers and 421 investigators of record. The latter consist of surgical, medical, endocrinologic, radiologic oncologists as well as pathologists and immunologists, emphasizing our multidisciplinary nature. The NSABP objectives are (a) to assess the worth of new and promising therapies when employed either alone or in concert with other modalities, (b) to allow for evaluation of the worth of modalities presently employed when used in innovative ways to test current biological hypotheses (c) to obtain biological and other pertinent data so as to better understand the natural history of patients with breast cancer permitting the formulation of better treatment strategies and (d) to enhance the quality of care of breast cancer patients by educating physicians to the findings and experiences of this group. Since 8/71 when Protocol B-04 was begun, six additional protocols were implemented to evaluate therapy in Stages I and II breast cancer. Almost 5000 eligible patients have been accrued and as of 12/78, 3916 (83%) were still alive and being followed. Over 1000 patients were still actively receiving protocol prescribed chemotherapy. During 1978 those patients generated approximately 50,000 forms and materials which required processing by the Statistical Unit. The present application is submitted so that efforts toward fulfilling the above documented objectives may be continued. More specifically, the aims are to (1) continue follow-up on all patients entered into NSABP protocols relative to treatment failure and survival, (2) complete patient entry on three ongoing protocols, (3) design and implement analyses of data obtained on all protocols relative to end results, acute and long-term toxicities, pathological and clinical discriminants and correlations, and biological measurements. These analyses will use multivariate techniques. Additional aims are (4) to develop and implement statistical methodology associated with cross-protocol comparisons, (5) implement appropriate biological investigations and (6) continue and extend quality control procedures to ensure the integrity of the treatment(s) administered and the validity of the long-term therapeutic results.